'Aidh bin 'Amr (May Allah be pleased with him) reported:
I visited 'Ubaidullah bin Ziyad and said to him: "Dear son, I heard Messenger of Allah (ﷺ) saying, 'The worst of rulers are those who treat their subjects harshly. Beware, lest you should be one of them."'[Al-Bukhari].
Arabic/English book reference: Book 1, Hadith 657